Roof ventilator



Oct. 3, 1944.

N. T. MavcKEN'zlE ROOF VENTILATOR Filed March 20) 1942 Patented Oct. 3, 1944 UNITED STATES PATENT OFFICE ROOF VENTILATOR Neal T. MacKenzie, St. Paul, Minn., assigner to General Timber Service, Inc., St. Paul, Minn., a corporation of Delaware Application March 20, 1942, Serial No. 435,540

3 Claims.

It is an object of this invention to provide a novel and efficient ventilator of simple, inexpensive, wood construction for use on the roofs of farm buildings and other structures.

The invention will be best understood by reference to the accompanying drawing in which:

Figure 1 is a. side elevation showing my improved ventilator on a building such as a grain bin;

Fig. 2 is a central vertical section through my device and a fragmentary portion of the building roof, and

Fig. 3 is a horizontal section taken on the line 3 3 of Fig. 1.

I provide a multi-sided tubular conduit. indicated generally by the numeral 4, which is formed from a multiplicity of plane wood members 5 of substantial length and relatively narrow width. The members 5 may be secured together at their side edges by suitable means such as adhesive and dowels or by other known fastening devices. It will be evident that the conduit 4 is substantially cylindrical and that it may be rigidly mounted in a suitable opening in a roof 6 of the building to be ventiltaed so that thelower end of the conduit communicates with the interior of the building.

Each of the members 5 is formed with a plurality of slots 1 which extend downward from the upper end to a point slightly above the roof 6. As best shown in Fig. 3, the spaced, parallel bars formed between the slots 'l have side edge surfaces 8 which extend obliquely to the radial planes through the respective surfaces. Each of these surfaces is preferably formed to extend at an angle of approximately 45 degrees to the outer and inner faces of the plane wood member `5 in which the slot is cut. All of the surfaces 3 are directed obliquely in the same circumferential direction indicated by an arrow in Fig. 3. The members 5 are preferably constructed from stock of nominal one inch thickness so that the oblique surfaces 8 have sufficient area to impart the desired swirling motion to the air currents which may be directed from any side of the building. To close the upper end of the conduit 4, I provide a suitable cap 9 formed with eaves projecting outward from the members 5. This cap rests on the upper ends of the members 5 and may be made removable to allow grain to be charged in through the conduit 4 when the building is used as a grain storage bin.

In operation, external air currents force air in through the slots 'l at the Windward side of the ventilator and the oblique surfaces 8-direct the internal currents circumferentially within the conduit 4. The resulting swirling motion causes solid particles and drops of water carried by the air to be thrown outward by centrifugal action with the result that the greater portion of the snow and rain that enters is prevented from settling into the building by being discharged through the slots l at the leeward side of the ventilator. The natural wind action on the oblique conduit surfaces 8 also draws out air from the interior of the building so that my device performs its Ventilating function efliciently.

By reason of the fact that the several members 5 are identical with each other and that they may be produced from standard lumber by simple saw cutting operations, my improved ventilator is rendered unusually inexpensive and easy to produce in quantities.

Having described my invention, what I claim as new and desire to protect by Letters Patent is:

l. A roof ventilator comprising a plurality of wood members secured together, edge to edge, to form a substantially cylindrical, upright conduit adapted to communicate at its lower end with the interior of the building to be ventilated, a multiplicity of slots being formed to extend longitudinally of the conduit through said members, a surface of each member formed by a slot being disposed obliquely to a radial plane through the slot and the several oblique surfaces being similarly directed, whereby air currents entering through the several slots are given a swirling motion within the conduit, and a closure for the upper end of said conduit having eaves projecting outward from the upper ends 0f the several slots.

2. A roof ventilator comprising a multiplicity of plane wood members of substantial thickness secured together, edge to edge, to form a substantially vertical conduit adapted to communicate at its lower end with the building to be ventilated, a multiplicity of vertically extending slots being formed in said members, and a surface of each member formed by a slot being disposed obliquely to the outer face of the member, whereby air currents entering through said slots are given a swirling motion within the conduit, and a cap closing the upper end of said conduit.

3. A roof ventilator comprising, a, multiplicity of wood bars of substantial thickness forming a .tubular conduit adapted to communicate at its lower end with the building to be ventilated, the axis of'said conduit extending substantially vertically, the several bars being spaced apart circumferentially of the conduit and a longitudinal surface of each of said bars extending obliquely inward tangentially to a circle concentric with said axis and of lesser diameter than the conduit to impart swirling motion circumferentially within the conduit to air currents entering between the bars, means connecting the lower ends of the bars together circumferentially of the conuit and a closure for the upper end of the con- NEAL T. MACKENZIE. 

